Sell Credits

Both public and private landowners can build new voluntary stormwater projects that can reduce flooding, boost resiliency,  and earn you money through StormStore.

Whether you have access to a spare parking lot or vacant land, developing your parcel to participate in the stormwater credit trading market can be a gift to your pocketbook and the planet.

Reach out to the StormStore team today! We help clarify the murky waters of stormwater credit trading by providing pro bono assistance for municipalities, private developers, community groups, and landowners in Cook County. Let us help you take advantage of the cost-savings benefits of participating in stormwater credit trading.

Is your project eligible?

How would StormStore work for your project?

If you're able to develop detention or retention in an eligible area, you now can earn money by selling stormwater credits. Depending on the type of stormwater management used onsite, there is potential for you to earn up to  $150,000 for every acre-foot of new stormwater storage you provide.

Follow the steps below to see where StormStore can help you navigate this innovative program and help you earn money.


To take advantage of this pilot, landowners can follow the following steps:

  1. Identify Opportunity - Work with a project engineer or planner to determine how much stormwater detention or retention you can build onsite.
  2. Find Credit Buyer - Identify a potential credit buyer who is willing to purchase your credits to meet their compliance needs.
  3. Obtain Permit Approval - Submit a watershed management permit to MWRD that documents your desire to provide supply credits for the pilot.
  4. Construct Project - Once you have received your permit, you are free to construct your project and sell your credits.  You will be responsible for maintaining the new stormwater infrastructure on your site in perpetuity.

Frequently Asked Questions

Simply put, it's a unit of stormwater storage. Each stormwater credit represents 1 acre-ft of stormwater retention or detention storage. You can buy and sell more or less than 1 acre-ft per trade depending on your project needs. For landowners looking to build new credit generating stormwater projects on their site, the only restriction in the number of credits that you can create is based on how much stormwater the project can receive from impervious surfaces, like rooftops, parking lots and roads, that are not already managed by other stormwater controls. The StormStore team may be able to help you figure out how many credits you are eligible to sell but you can also contact an engineer in your area to calculate your site’s credit generating potential.
During this pilot phase there is no cost to participate in StormStore so it's a great time to consider StormStore to meet your stormwater compliance needs! The StormStore team is currently providing administrative services pro bono to early participants who are looking at buying or selling credits. Let us help you assess your site, find your match and negotiate a trade...
Do you have access to stormwater detention or green infrastructure? You can generate credits with any new, voluntary stormwater facility, including green infrastructure, but some credit-generating projects will be more cost effective than others. Some factors to consider when thinking about building a any new green infrastructure or detention project include: 1) Selecting areas on your site that are not needed for other uses or part of future redevelopment plans 2) Selecting areas that can receive stormwater runoff from relatively large impervious areas (roofs, parking lots, etc.) that are not currently managed by other stormwater facilities 3) Selecting areas of your site where there are not a lot of underground utilities 4) Selecting areas that are easily accessible for maintenance Sites that are relatively small (typically less than 0.5 acres in size) or single-family homes are not likely to be cost-effective. Get in touch with the StormStore team if are planning a construction project, thinking of improving your landscaping, or if you have space to spare to help reduce flooding in your community so we can see how StormStore can make your property work for you.
Property owners who are already planning construction or landscaping improvements on their property may want to consider installing credit generating stormwater facilities at the same time. This is an especially good option for sites that do not trigger MWRD’s stormwater management regulations because any stormwater runoff retained or detained by the new project may be eligible to generate credits.
Any non-single family home landower located in the Little Calumet or Lower Des Plaines Watershed Planning Areas can build an off-site facility and generate credits on their site, regardless of the size and type of project. A few things to consider for those landowners who are interested in generating credits: 1) Any credit generating stormwater detention or retention projects must be new and voluntary. Both detention controls, such as wet/dry stormwater ponds, and retention volume controls, like rain gardens, permeable pavers, or other types of green infrastructure are eligible to trade through StormStore. Developers and landowners can also generate credits by installing new stormwater controls in excess of what is required under MWRD’s WMO, as long as it is shown that the excess storage is used to capture runoff from impervious surfaces that are not already managed by other stormwater controls. 2) Any credit generating project must have an approved watershed management permit and pass MWRD’s construction inspection, regardless or size or type of project (even those type of projects that are considered exempt under the WMO) 3) Landowners who generate credits for StormStore must also provide a maintenance contract and sign a sale agreement with the credit buyer and agree to provide long-term maintenance of new stormwater facilities.
There are no conditions that limit who can build, buy or sell projects as long as eligibility criteria are met or restrictions on where projects can be built and traded in the pilot Lower Des Plaines and Little Calumet watershed planning areas. The only requirement is that credits can only be traded within the same watershed. This means that if you build a rain garden in the footprint in the Little Calumet Watershed Planning Area you can only sell or trade credits to potential buyers who are developing projects in the Little Calumet watershed area.
The cost of each credit will need to be negotiated on a trade by trade basis between the buyer and seller. Typically the seller will set the sale price based on the total pre-planning, planning, design, construction and long-term maintenance costs for the facility they build. Even with all these costs included the credit price will often result in cheaper, easier, and greener stormwater management projects for buyers. Currently there is no maximum or minimum credit price - however we have seen early estimates of credit prices that range from $150,000 to $300,000 per credit (or per acre-ft of storage). This number will vary and generally depends on the type of credit being offered (detention vs volume control) and the type of stormwater facility used to generate the credit (grey vs green). The StormStore team can help credit generators figure out the right price point for them and walk you through how to negotiate with potential buyers.
MWRD does not currently certify credits but does track trades through their existing stormwater permit process. To ensure compliance with MWRD’s WMO and secure a trade, buyers must submit a stormwater permit for approval and identify the offsite facility that will be used to meet stormwater management obligation using the offsite facility’s MWRD issued permit number. The buyer will also need to share the purchase or trade agreement made with the offsite facility owner with MWRD prior to project construction.
Landowners who generate credits are required to maintain the stormwater facilities in accordance with MWRD's Technical Guidance Manual and the site’s MWRD-approved Stormwater Management plan. This maintenance obligation is in perpetuity for the life-cycle of the facility you construct. All projects generating credits must pass a MWRD inspection per the WMO. As part of your stormwater permit a maintenance contract and maintenance plan that details the specific actions to be taken for site maintenance must be prepared and approved by MWRD.
Contact Ryan Wilson, Manager of Water Resources at the Metropolitan Planning Council for more information. You can reach him at


Let's Talk StormStore (Infographic)

StormStore: So buyers and sellers of stormwater credits can easily make a deal! Learn more »

Training Webinar (Video)

Designed for civil engineers, this webinar showcases the pilot program and answer questions about what projects are a good fit. It will also describes the pro-bono support available through the StormStore partnership. Learn more »

Municipal Guide (PDF)

Brief handout for municipal staff who are interested in StormStore. Learn more »


Contact the StormStore team today!

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